valve adj. on engine while on engine stand before. start up

The Hemi instructions in the FSM are based on hydraulic lifters and adjustable ductile iron rocker arms and the instructions call for 1&1/2 turns in. The Direct Connection Engine book has instructions based on using 273 factory adjustable rockers on any LA small block and it calls for the same thing, but everybody I know that uses an adjustable hydraulic system does 1/2 turn with good results. I'm just wondering why the discrepancy...